The invention relates to a device for positioning X-ray films between at least one pair of intensifying screens. The screens are first spread apart to accept the film and then brought together again with the film, ready to be exposed, sandwiched between them. The device consists of two rollers, an endless band, a grip cleat, and a press. At least one of the rollers is powered, and the second is mounted at an interval from and parallel to the first. The grip cleat is mounted parallel to the rollers and on the continuous band so as to grip the pair of intensifying screens along one longitudinal edge. The press forces the intensifying screens and film together.
A device of this kind is known from British Pat. No. 1,490,276. It has the following disadvantages:
(a) It requires two continuous upper and lower bands, and consequently two pairs of rollers.
(b) It is relatively tall, and there is not much space under X-ray tables, because other equipment has to be kept there.
(c) Since X-ray films show shadow images of transillumnated bodies, the farther the surface of the film is from the subject, the greater the undesirable enlargement of the image and the more serious the problem of umbra and penumbra. The exposure position in the known device is at the bottom of the upper band, so that the film-to-subject distance is increased by at least the distance from the top to the bottom of the band.
(d) The press consists of two moving plates, so that more must be spent on mounting them and on controlling and powering their motion.